TEHRAN, Iran — Iran's supreme leader said Thursday that he was willing to restore diplomatic relations with the United States but doing so now would make his country more vulnerable to U.S. espionage.

"I would be the first one to support these relations," said Ayatollah Ali Khamenei, during a student group meeting in the central Iranian province of Yazd.

"Of course we never said the severed relations were forever," added Khamenei, 69, who has final say in all state matters. "But for the time being, it (restoring ties) is harmful and we should not pursue it."

Khamenei said restoring ties with the U.S. now would "provide an opportunity for security agents to come and go, as well as for espionage."

"It has no benefit for Iranian nation," state radio quoted him as saying during the meeting. It would be an "opportunity for U.S. infiltration, traffic of their intelligence agents and espionage on Iran."

Severed diplomatic ties
The United States and Iran have had no diplomatic ties since shortly after the 1979 Islamic Revolution, when militant students seized the U.S. Embassy in Tehran and published sensitive documents they found inside documenting American intelligence-gathering in the country. The embassy, labeled the "Den of Spies," is occasionally open to public as a museum documenting American misdeeds in Iran and the region.

The Swiss embassy in Tehran represents the U.S. in Iran, while the Iranians have an interest section in Pakistan's embassy in Washington.

Iran last year claimed it had uncovered spy rings organized by the U.S. and its Western allies and detained four Iranian-Americans, who were later released. The arrests prompted the United States to warn its citizens against traveling to Iran, accusing authorities there of a "disturbing pattern" of harassment.

The dispute over Iran's nuclear program and U.S. allegations of Iranian support for armed groups in Iraq have further raised tensions.

Three rounds of talks
Washington has refused to hold talks with Iran over the issue of diplomatic ties until Tehran suspends uranium enrichment, a process that can be used to produce fuel for both nuclear energy and weapons.

But the two countries have held three rounds of ambassador-level negotiations on security in Iraq, breaking the 28-year diplomatic freeze.

Iran says its nuclear program is intended solely for energy production, and Khamenei reiterated Thursday that his country would continue to pursue it to generate some 20,000 megawatts of electricity in the next two decades.

Washington's push for a third round of U.N. sanctions against Iran was undermined by the release of a new U.S. intelligence report in December, saying that Tehran suspended development of nuclear weapons development under international pressure in 2003. It was a dramatic turnaround from the previous U.S. stance that Iran restarted the program in 2005.

Copyright 2008 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.